Poly(hydroxy ether)s, or phenoxy resins, are linear polymers typically prepared by copolymerization of 2,2-bis(4 hydroxyphenyl)propane (bisphenol A) with 2,2-bis(4-hydroxyphenyl)propane-epichlorohydrin polymers (epoxy resins). Phenoxy resins contain about 6 percent by weight secondary alcohol groups.
Phenoxy resins are used to enhance the properties of coating, adhesive, ink, composite, fiber, and plastic compositions. The pendant hydroxyl groups and backbone ether linkages promote wetting and bonding to polar substrates, pigments, and fillers. The addition of phenoxy resin to thermoplastics can help control process rheology in extrusion, molding, and film forming operations. The amorphous nature of phenoxy resins can be helpful in controlling the crystallization kinetics of thermoplastic materials.
Phenoxy resin has a solubility parameter of 10.68, which gives it excellent compatibility with polar polymers, such as polyesters, polycarbonates, polyamides, and polyurethanes. However, phenoxy resins have low compatibility with polystyrene, poly(arylene ether), polyolefins, (meth)acrylics and other non-polar polymers. The low compatibility of phenoxy resins with non-polar polymers limits their usefulness as additives for non-polar polymers, and also limits their usefulness as compatibilizing agents for blends of polar and non-polar polymers.
Despite the useful properties of phenoxy resins, there remains a need in the art for a material that maintains the advantageous properties of phenoxy resins, while having compatibility with both non-polar and polar polymers, so that it can be used in either. There also remains a need in the art for a material that can serve as a compatibilizing agent for blends of non-polar and polar polymers.